Abaixo está uma instrução que descreve uma tarefa de geração de SQL, combinada com uma entrada que fornece mais contexto sobre os esquemas de tabela disponíveis. Escreva o código SQL que responda adequadamente à solicitação
 ###Instrução: Me diga a liga com uma temporada regular de 1º.
 ###Tabelas: CREATE TABLE papakura_local_board (papakura_local_board_id AUTO_INCREMENT PRIMARY KEY, Name VARCHAR, Years VARCHAR, Gender VARCHAR, Area VARCHAR, Authority VARCHAR, Decile INT, Roll INT) CREATE TABLE passages (passages_id AUTO_INCREMENT PRIMARY KEY, Incumbent VARCHAR, Reason for Vacancy VARCHAR, Appointed Successor VARCHAR, Date of Appointment VARCHAR, Elected Successor VARCHAR, Date of Election VARCHAR) CREATE TABLE stadiums (stadiums_id AUTO_INCREMENT PRIMARY KEY, Stadium VARCHAR, City VARCHAR, Capacity INT, Matches played INT, Overall attendance INT, Average attendance per match INT, Average attendance as % of Capacity VARCHAR, Overall goals scored INT, Average goals scored per match VARCHAR, Elevation VARCHAR) CREATE TABLE year-by-year (year-by-year_id AUTO_INCREMENT PRIMARY KEY, Year VARCHAR, Division VARCHAR, League VARCHAR, Reg. Season VARCHAR, Playoffs VARCHAR, Open Cup VARCHAR) CREATE TABLE american_television (american_television_id AUTO_INCREMENT PRIMARY KEY, Year VARCHAR, Network VARCHAR, Play-by-play VARCHAR, Color commentator(s) VARCHAR, Ice level reporters VARCHAR, Studio host VARCHAR, Studio analysts VARCHAR)  
SELECT League FROM year-by-year WHERE Reg. Season = 1st